Method of dissecting tissue layers

ABSTRACT

A fluid operated retractor for use in surgery. The retractor has a portion that is expandable upon the introduction of fluid under pressure. The expandable portion, is made of a material strong enough, and is inflated to enough pressure, to spread adjoining tissues within the body. The retractor is especially useful in fiber optic surgery because it can be inserted percutaneously through a small opening then expanded to a much larger dimension when in the desired location, to retract tissue from within. The retractor may be used to spread a joint such as a knee joint or a shoulder joint, or may be used to separate tissue planes generally, to improve visualization and create a working space for the surgeon.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application of application Ser. No. 08/464,143,filed on Jun. 5, 1995, now Pat. No. 6,187,023 which is a file wrappercontinuation of 08/593,299, filed on Jan. 29, 1996, now U.S. Pat. No.6,017,305, which is a divisional of U.S. application Ser. No.08/419,851, filed on Apr. 10, 1995, abandoned, which is a continuationof U.S. application Ser. No. 08/216,097, filed on Mar. 22, 1994,abandoned, which is a continuation of U.S. application Ser. No.08/054,416, filed on Apr. 28, 1993, abandoned, which is a divisional ofU.S. application Ser. No. 07/731,534, filed on Jul. 17, 1991, now U.S.Pat. No. 5,163,949, which is a divisional of U.S. application Ser. No.07/487,645, filed on Mar. 2, 1990, now U.S. Pat. No. 5,331,975. Thepriority of these prior applications is expressly claimed and theirdisclosure is hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to tissue retractors, for use in medicine.More particularly, the present invention relates to fluid operatedapparatus for use in moving apart abutting tissues, during surgery, inorder to create a space between the tissues to improve visualization andfor increased working space during open surgery and fiberoptic assistedsurgery.

2. Description of the Prior Art

Current methods used for retracting tissue and improving visualizationare mechanical separation using metal retractors during open surgery, orthe direct pressure of an unconfined flow of fluid such as water or CO₂during fiberoptic surgery. A typical mechanical external fixator haspins driven through the bones and mechanically distracts the elements ofthe joint. Problems with the water method include fluid extravasationincluding into and through the tissue itself. Increased pressure andswelling result in the area, resulting in edematous or swollen tissue.Excess pressure from mechanical retractors may cause necrosis or tissuedeath. With these methods, it is impossible to monitor the pressurebeing applied to the body tissues, and tissue damage or necrosis canresult.

While operating from within the body, i.e., fiber optic assisted surgeryas opposed to open surgery, there is no known way to selectively move orretract tissue, either hard tissue such as bone or soft tissue, out ofthe way to improve visualization. No device in use adequately allows asurgeon to create an actual space or expand a potential space in thebody, by separating adjacent layers of tissue. The prior art does notdisclose a retractor that is powerful enough and made of a material thatis strong and resilient enough to, for example, separate tissue planesfrom within. Such a device, especially in the field of fiber opticsurgery, would allow a surgeon to visualize and operate without usingthe conventional bulky and awkward mechanical retractors that requirelarge open incisions. Such a device would also permit working within thebody without damaging a great deal of tissue in the path between theskin opening and the working area, by minimizing the external orifice orskin incision.

SUMMARY OF THE INVENTION

The present invention is a system of retractors that a surgeon can useto take potential spaces within the body and turn them into existingspaces safely and easily and controllably in order to safely visualizeappropriate tissue and operate. The retractor selectively movesappropriate tissue out of the way to enable a surgeon to see and workbetter within the body, and selectively moves body parts such as jointparts or soft tissue planes in order to create a space between thetissues for visualization and for working.

The retractor of the present invention includes a fluid-operated portionsuch as a balloon or bladder to retract tissue, not merely to work in ordilate an existing opening as for example an angioscope does. Thefluid-filled portion is flexible, and thus there are no sharp edgeswhich might injure tissue being moved by the retractor. The softmaterial of the fluid-filled portion, to an extent desired, conforms tothe tissue confines, and the exact pressure can be monitored so as notto damage tissue. The expanding portion is less bulky and more compact,and the pressure it applies at the tissue edges can stop bleeding of cuttissue. These are all features not possessed by a conventionalmechanical retractor.

With a typical mechanical retractor, the opening in the skin and thenceinwardly must be larger than the surgical area being worked upon, inorder to be able to get the mechanical retractor into position. Thesurgeon must damage a large amount of tissue that may be healthy, inorder to expose the tissue to be worked on. The retractor of the presentinvention minimizes damage to tissue in the way of the tissue thesurgeon needs to expose, which was previously cut in a large openexposure. With the retractor of the present invention, the opening atthe skin is smaller at the skin where the device is inserted, and widerat the location inside the body where the retractor is expanded. Theretractor is first placed into the body in an unexpanded condition, andthen, as it is expanded, pushes tissue out of the way in deeper layersof the body one can see and safely operate on affected tissue. Thus,less undesired tissue damage occurs.

The bladder is pressurized with air or with water or another fluid. Thefluid used in the bladder must be safe if it accidentally escapes intothe body. Thus, besides air, such other fluids as dextrose water, normalsaline, CO₂, and N₂ are safe. The pressure in the bladder is monitoredand regulated to keep the force exerted by the retractor at a safe levelfor tissue to prevent tissue necrosis. The retractor can exert apressure on the tissues of as high as the mean diastolic pressure of 100mm of mercury, or higher for shorter periods of time, while still beingsafely controlled. Typical inflatable devices such as angioscopes do nothave anywhere near the strength, or the ability to hold enough fluidpressure, or shapes to retract tissue as described herein. As comparedto prior art devices, the retractor of the present invention operateswith greater pressure within the bladder, since it is made of strongermaterials such as Kevlar or Mylar which may be reinforced with stainlesssteel, nylon, or other fiber to prevent puncturing and to providestructural shape and support as desired. Such materials are strongenough to hold the necessary fluid pressure of about several pounds orup to about 500 mg Hg or more and exert the needed force on the tissueto be moved. The choice of material is well within the ability of onefamiliar with such materials and accordingly will not be gone into infurther detail herein. The present retractor is thus able to exertsubstantially more force on adjoining tissues than a prior art device.The shapes of the retractors are specific for each application, and mayinclude separate variable chambers which are sequentially controllable,to control the direction of tissue retraction.

GENERAL DESCRIPTION OF THE INVENTION

The fluid-filled portion of the retractor is preferably a unitaryportion such as a bladder. In this case, the bladder is expanded withthe introduction of fluid under pressure. Alternatively, thefluid-filled portion of the retractor may include a series of prongs orfilaments that expand radially outwardly upon the introduction of fluidunder pressure. The prongs themselves may be expandable, or there may bean expandable portion located centrally of all the prongs which, when itexpands, forces the prongs outwardly.

Typically, the height of the bladder, that is, its width or transversedimension, is significantly greater than its length (axial orlongitudinal dimension). The bladder expands primarily in width only,not in length, although the shape will vary with the application. Thisis in accordance with the purpose of the device which is to enable theseparation of adjacent tissue layers to, for example allow improvedvisualization in front of a scope inserted between the tissue layers.

The retractor of the present invention can be used to direct or positionthe end of a scope relative to the tissue walls. The retractor can alsobe used to stabilize the end of a scope. When a camera is being used viathe scope, the scope often moves or jumps around because of theflexibility of the end of the scope. This is prevented by inflatingbladders at the tip or along the shaft of the fiberoptic scope tocontrol the direction of the tip of the scope and thus stabilize thescope, leaving both hands free to work and providing a stable image forthe surgeon.

Surgeons operate along tissue planes. Once a surgeon finds a tissueplane, he dissects along it, starting the separation process with theknife. The retractor holds the tissue layers apart and helps and easesin defining and further separating the tissue layers as the surgeonoperates along the tissue planes, helping to spread and define theplanes. The retractor helps to separate the tissue layers, increasingthe space for operating, and improving the surgeon's ability to separateand visualize, leading to better and safer surgical technique.

A preferred use for the present retractor is in the field of fiber opticsurgery, including endoscopy, arthroscopy, laparoscopy, etc. whichrequire looking into and operating within a limited space with a fiberoptic light and camera. The open or existing spaces in joints aregenerally too small to permit easy operation and visualization. In thePrior art, only direct (unconfined) water or air pressure is used toexpand the joint capsule or tissue in the joint. This may actually pushtissue in front of the scope, obscuring vision. The present retractordistracts a joint directly to make it easier to see inside (around) thejoint. A sleeve which can be a malleable or rigid sheath may optionallybe provided to protect the tissue as the bladder is slid in and out ofthe end of the cannula once in the work area within the joint. Thebladder expands into an area of soft tissue-for example the bursa-andpushes it out of the way. The bladder can be left in place during theoperation, or it can be deflated and removed, and the arthroscope andother instruments can be put into the space created.

An alternative preferred use for the retractor of the present inventionis to operate in a joint of the spine, and specifically between twovertebrae. The retractor is used to spread two vertebrae apart to enableremoval of the spinal disc from between the vertebrae.

Other uses of the retractor are as an occluding device to stop bloodflow from an anastomosis or angioscopic procedure, or to stop backflow(retrograde flow) of stomach or colon contents. The retractor of thepresent invention is also suitable for use in the tempomandibular joint.Specifically, a dentist or oral surgeon uses an appropriately shapedretractor to hold open the jaw of a patient while the dentist or oralsurgeon works on the mouth of the patient. The inflatable retractor ismuch more comfortable to the patient than a rigid metal or plasticdevice, it conforms to the jaw structure rather than pressing unevenlyagainst it, and lessens fatigue. Thus it is safer for the dentist bysafely maintaining the two rows of teeth spaced apart and by increasingvisibility for working, while at the same time being easier for thepatient.

The retractor can also be a useful diagnostic tool. The strength orpressure or resistance of tissue can be measured by the pressurerequired to move it.

The bladder may be a bellows type device in which the material does notstretch but which expands when pressurized from within and which iscollapsed by the use of suction. In this case, it would preferably bemade of a polymer of the class including Kevlar or Mylar fabric forstrength and structural integrity. The bladder may generally also bemade from any very thin walled polymer.

The bladder may also be made from a biocompatible and/or biodegradablematerial, so that if it can not be removed from the body for somereason, or if the surgeon desires to keep the bladder in place in thebody for a period of time, it will not damage the tissue and mayeventually be resorbed into the body. Such a biodegradable bladder maybe left under the skin postoperatively to stop postoperative bleeding orto keep tissue expanded. Alternatively, the bladder may be made of astretchable material which stretches when pressurized from within, andthen collapses partially of its own accord when depressurized or alsowith the help of suction. The retractor may be transparent for bettervisibility, but it need not be for some applications. Also, theretractor can be disposable. The material choice is within the skill ofthe art. One surface of the bladder may be made of or have thereon areflective surface to reflect light to see around a corner.

The retractor can be used as a joint jack that is, to distract a jointfrom within in one area and provide ease of access through the joint.Less damage to the joint occurs if the tissue edges are spaced apartduring a procedure. When placed between two joint surfaces it pushesthem apart from within, increasing the space available for visualizationand/or the working space. The retractor stabilizes a joint when expandedbecause it forces the tissues to remain in one place.

Another use is to look directly at a neurovascular bundle, retract itout of the way, and then operate around it. For example, the surgeon cango into the back of a knee, inflate the retractor, identify theneurovascular bundle and then be able to work around it. The task ismade easier by the ability to separate tissue layers from within. Onemay cup the tissue then push it out of the way, in the nature of anumbrella opening, to protect vital tissues to operate safely aroundthem.

Depending on the application, the retractor can be left in place whilethe work (or looking) is being done, or it can be deflated and thentaken out to allow a scope or other instrument to be put in. Sometissues will stay in place to allow this latter function, after thespace has been created with the retractor.

A most typical construction for the retractor of the present inventionis an inflatable bladder situated on the end of a shaft, which may beflexible or rigid, which is pushed through an extra opening in a scopeor cannula or through a separate portal, and which expands at the end ofthe shaft.

The retractor can be located on a scope, either on the end thereof ormovable axially through a channel along the length of the scope. Theretractor can alternatively be mounted on a cannula. The retractor canbe mounted on a separate shaft passing through an existing channel in acannula; it can be inserted through a separate hole in the cannula orthe scope; or it can be inserted through a separate opening in the body.The shaft with a retractor on the end can be pushed or slid through thecannula, side by side with a scope. Alternatively, the bladder canexpand out of, then recess back into, a groove on a cannula or scope.The retractor can be used to create a space right from the end of thescope.

The bladder itself can be round, eccentric, oval, conical, wedge-shaped,U-shaped, curved, angled, or it may be in any shape desirable tooptimize the particular application. The bladder may be irregularlyshaped when inflated, that is, it may expand to a greater radius in thearea where it is desired to look (where greater exposure space isneeded).

Vacuum can be used to deflate the bladder. The bladder may then beremoved by sliding it out the portal directly.

In one embodiment the retractor includes a spring loaded sleeve whichslides axially over a plurality of plates or prongs, plastic or metal. Acentrally located motive force is provided to move the prongs outwardlyto retract the tissue, which force may be mechanical or a separateinflatable device. Alternatively, each filament is a tube which expandsand straightens out as air pressure is added (as it is inflated) andthus moves radially outwardly to retract adjoining tissue. The filamentsplates or prongs are controllable and covered by a sheath, which slidesoff them proximally axially to allow them to be inflated and expand, andthen, after they have been deflated, slides distally along the shaftover the filaments to cover them and allow the device to be movedthrough the body. When the sleeve retracts the prongs or filamentsexpand radially outwardly to push tissue away from the scope to improvevisualization.

The retractor can be disposed at the end of a flexible sheath. Theretractor can be directable with cables, or with compressed air, to turnor bend in a certain direction.

The present invention also provides a new type of self-retainingretractor which is more compact and is disposable for use in opensurgery. The retractor is used to hold tissues laterally, pushing tissueedges apart. For such an application, the retractor includes a U-shapedbladder which is a tube which acts like a spring and under high pressureattempts to straighten itself out when inflated. The deflated tube-likestructure is first properly positioned within the wound. As theretractor is inflated, it tries to straighten out, and thus opens thewound, As it presses on the edges of the wound, it compresses tissueedges, giving a hemostatic effect. For example, if the retractor is putvertically into a wound, it expands the deep tissues. The retractor canalso use the inflatable bladder to push apart metal or plastic plates topush apart tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention will become apparent to thoseskilled in the art to which the present invention relates from readingthe following specification with reference to the accompanying drawings,in which:

FIG. 1 is a schematic view of a retractor in accordance with the presentinvention shown in the unexpanded and expanded conditions;

FIG. 2 is a schematic view of a retractor extending through a cannulaand mounted on the end of a separate shaft;

FIG. 3 is a schematic view similar to FIG. 2 illustrating the use of afiber optic scope with the retractor;

FIG. 4 is a schematic view showing a retractor inserted through aseparate side opening in a cannula;

FIG. 5 is a schematic view of a few of the many and various shapes inwhich the inflatable portion of the retractor may be formed;

FIG. 6 is a schematic view of a retractor shown mounted on the end of acannula and having an opening therein for a scope to pass through;

FIG. 7 is a diagram of a fluid supply system for operating a retractor;

FIG. 8 is a view illustrating the use of a retractor to position the endof a scope;

FIG. 9 is a schematic view illustrating the retraction of soft tissuefrom bone;

FIG. 10 is a schematic view of a retractor shown in use in a shoulderjoint;

FIG. 11 is a schematic view of a retractor shown in use in a knee joint;

FIG. 12 is a schematic view of a second embodiment of a retractor shownin use in a knee joint;

FIG. 13 is a schematic view illustrating the simultaneous use of tworetractors to retract tissue;

FIG. 14 is a schematic view illustrating the simultaneous use of tworetractors to create an open working space in a digestive tract;

FIG. 15 is a schematic view showing two retractors being used togetherto create an open working space in a blood vessel, or a working spacefrom potential space created between the two expanded bladders;

FIG. 16 is a schematic view illustrating the relatively large size of anexpanded retractor compared to the relatively small size of thepercutaneous incision;

FIG. 17 is a schematic view showing a retractor used for percutaneousbone access;

FIG. 18 is a series of schematic views illustrating another embodimentof the fluid-expandable portion of the retractor of the presentinvention;

FIG. 19 is a series of schematic views illustrating a retractor of thepresent invention suitable for use in open surgery;

FIG. 20 is a series of illustrating the provision of a plurality ofseparately inflatable bladders on one supporting structure;

FIG. 21 is a schematic view illustrating the use of retractors of acertain shape to create a visualization and working space;

FIG. 22 is a schematic view illustrating the use of retractors of acertain shape to create a visualization and working space;

FIG. 23 is a schematic view illustrating a retractor having a reflectivesurface thereon; and

FIG. 24 is a series of views illustrating a retractor of the presentinvention suitable for use in carpal tunnel surgery.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates schematically a retractor 10 in accordance with thepresent invention. The retractor 10 includes a fluid supply structure 12and an expandable balloon or bladder 14 located at or near the end ofthe structure 12. The bladder is expandable, under the force of fluidunder pressure, from an unexpanded condition as indicated in full linesat 14 to an expanded condition as shown in broken lines at 16. In theexpanded condition, the transverse dimension 18 of the bladder 14 issignificantly greater than its transverse dimension before expansion,the longitudinal dimension 20. Also, in the expanded condition, thetransverse dimension 18 of the bladder 14 is significantly greater thanits longitudinal dimension 20.

When the bladder of the retractor is expanded inside the body, itretracts tissue. As seen in FIG. 2, a bladder 22 is mounted on the endof a separate shaft 24 within a cannula or scope 26. The cannula orscope 26 has been inserted into the body through an opening 28 in theskin (either preexisting or made in situ) which has atransverse-dimension 30. The bladder 22 when in its unexpanded conditionas shown in broken line is smaller than the dimension 30 of the bodyopening, but when expanded, it expands to a dimension 32 which issignificantly greater than the dimension 30. An actual space or workingspace 34 is formed which was not present before the expansion of thebladder.

The newly-formed working space may be used, for example, for better useof a fiber optic scope as illustrated in FIG. 3. In FIG. 3, a retractor10 is passed through an opening 36 in a cannula 38. A fiber optic scopeshown schematically at 40 is also passed through the cannula 38. Thecannula 38 is inserted into the body through an opening in the bodytissues 42 which is only as large as the outer diameter of the cannula.38. The retractor 10 is then inflated, with air or another fluid beingsupplied through a rigid or flexible shaft 44 to an expandable bladder46. The bladder 46 expands transversely, retracting the tissues 42transversely and creating a working space 34. By axial manipulation ofthe shaft 44, the bladder 46 is movable either toward the end of thescope 40 in the direction as indicated by the arrow 48, or away from theend of the scope 40 as indicated by the arrow 50, as desired. Suchmanipulation of the retractor can selectively move and place theadjoining body tissues where the surgeon wants them to enable better useof the scope 40 by the surgeon.

As shown in FIG. 4, the retractor 10 may be inserted into a cannula 52through a separate opening 54 therein. The opening 54 is shown on theside of the cannula 52, although, of course, it may be on the end of thecannula as is typical. Alternatively, the retractor 10 may be insertedinto the body through an opening in the body tissues separate from theopening through which the fiber optic scope is inserted. Either of theseoptions allows for greater flexibility in the insertion and positioningof the retractor 10 relative to the other instruments being used such asthe arthroscope.

Also as indicated in FIG. 4, the bladder 58 may be eccentric oreccentrically located relative to the opening 60 at the junction betweenthe bladder 58 and the shaft 62. This is accomplished by using knowntechniques to form the bladder 58 of a material construction, and shapesuch that of it expands into the eccentric shape as illustrated in FIG.4 when inflated by fluid under pressure through the shaft 62. In thismanner, an improved visualization and working space 34 is created whichis eccentrically located relative to the other instruments being used.This may be preferable when the surgeon is using an angled scope.

FIG. 4 is illustrative of the fact that the bladder of the retractor ofthe present invention may be formed so as to expand into any particularshape as desired for the particular application. This feature is alsoshown schematically in FIGS. 5A through 5E which illustrate,respectively, retractor bladders which assume in their expanded statesin round, oval, eccentric, oblong, and conical shapes. Such shapes maygenerally be called “non-uniform” shapes for purposes of the presentinvention, and retractors with such a shape will expand in a“non-uniform” manner. Such shapes may include, for example, wedge- orU-shaped filaments that collapse at the skin, then expand at deep tissueplanes for visualization and working space. The bladder may also cup andprotect vital tissues such as nerves and arteries while working on othertissues such as muscle.

Another typical form of construction is illustrated in FIG. 6, whichshows a bladder 64 that in its expanded condition assumes a toroidalshape. Again, the width 66 of the bladder 64 is significantly greaterthan its length 68. The bladder 68 is expanded by fluid under pressurereceived through a fluid channel 70 formed between a cannula or scopeouter wall 72 and inner wall 73. By virtue of the toroidal shape of thebladder 68, the leading end 74 of the scope 76 may be passed axiallycompletely through the retractor into the working space 34 which hasbeen created in the tissues 78. Such a bladder 64 may also be mounted ona separate shaft inserted through the scope of the cannula.

In all cases, the fluid pressure within the bladder of the retractor ismonitored and controlled to keep the force exerted by the retractor at asafe level for tissue to prevent tissue necrosis. As indicatedschematically in FIG. 7, a retractor 10 is supplied with fluid underpressure from a fluid pressure source 80 via a fluid supply line 82. Aregulator 84 controls the supply of fluid to the retractor 10. Apressure sensor 86 is located within the retractor 10 and senses thepressure of the fluid within the retractor 10. The pressure sensor 86sends a signal which is representative of the fluid pressure within theretractor 10, via wiring 88, to a monitor 90. The monitor 90 isconnected via control wiring 92 to the pressure regulator 84. Thepressure of the fluid within the retractor 10 may thus be monitored andcontrolled either manually or automatically, by means which are wellknown in the art and so need not be described further herein. The source80 of fluid supply may be, for example, the air pressure supply which iscommonly found in hospital operating rooms.

By virtue of this ability to monitor the pressure within the retractor10, the retractor 10 can also be a useful diagnostic tool. The strengthor pressure or resistance of tissue to movement can be measured by thepressure required to move it.

FIGS. 8 and 8A illustrate the use of a retractor of the presentinvention to stabilize a fiber optic scope. The retractor 10 (FIG. 8)includes a bladder 94 which retracts the body tissues 96 away from thescope 98. Since the bladder 94 engages and pushes radially outwardly onbody tissues 96 all around the scope 98, the retractor becomes fixed inposition when it is so expanded. If the bladder 94 is fixed to the endof the scope 98, the retractor 10 thereby fixes the end of the scope 98in position relative to the body tissues 96. When a camera is being usedwith the scope 98, the picture normally moves or jumps around because ofthe movability of the end of the scope 98. This is prevented by so-usingthe retractor 10 to stabilize the scope 98, leaving the surgeon withboth hands free to work and a steady view of the work area.

FIGS. 8 and 8A also illustrate how the retractor of the presentinvention can be used to control the placement of the tip of a fiberoptic scope. The retractor 10 is formed with an eccentric bladder 94which retracts the body tissues 96 away from the scope 98 to a greaterdistance in one direction than in another. Thus, by rotating theretractor 10, the surgeon can place the tip of the scope 96 closer tothe body tissue 100 (FIG. 8) on one side of the working space 34, or tothe body tissue 102 (FIG. 8A) on the other side of the working space 34.Such variable placement can, of course, also be attained via use of aretractor 10 that includes a bladder that can be expanded to varyingshapes.

The retractor of the present invention has many uses in the surgicalfield. FIG. 9 illustrates the use of a retractor 10 to retract softtissue from bone, for example within a joint. The retractor 10 isinserted between the bone 110 and the soft tissue 112. The bladder 104is then expanded. The soft tissue 106 is forced away from the bone 104.The surgeon may then use a fiber optic scope or other instrument to workwithin the working space 34 created by the retractor 10. The retractorof the present invention can provide the force needed to move the softtissue 112 away from the bone 110 may vary, between about 100 and 1000mm Hg, and thus, it is important to maintain the proper pressure betweenthe two. The retractor 10 can do this since it operates on high fluidpressures of about 10 to 1000 mm Hg and it utilizes a high strengthmaterial such as Kevlar, Mylar, or another durable polymer such asPolylite®, a product of Reichhold Chemicals, Inc. This simple retractionof soft tissue from bone would otherwise be impossible.

FIG. 10 illustrates the use of a retractor 10 to enable a surgeon towork within a shoulder joint. The joint includes the humeral head 114,the glenoid 116, the acromium 118, and the acromium joint 120. Therotator cuff 122 is attached to the humeral head 114. A scope 124 isinserted preferably from the back of the shoulder joint. In the priorart method, the acromium 118 can be separated from the bone from withinthe joint, in order to gain access to the rotator cuff, only byintroducing an unconfined stream of water into the joint as indicated at126. This method leads to the presence of water everywhere, includingwithin the tissues themselves, and is not a desirable method. Inaccordance with the present invention, a retractor 10 with an expandablebladder is simply inserted through a small incision in the skin andinflated to expand in the direction indicated by the arrow 130, thusretracting the tissue space. There is no unconfined fluid introducedinto the tissue space, and the degree of separation of the joint iseasily and safely controlled by controlling the pressure within theretractor 10.

FIGS. 11, 11A, 12, and 12A illustrate the use of a retractor 10 toenable a surgeon to better work within a knee joint. The joint includesfemur 132 and tibia 134 and between them a neurovascular bundle 136which the surgeon wishes to work on (or work around). However, thenormal space 138 within the tissue space is so small as to make workingwithin the joint very difficult or impossible. Accordingly, a retractorthat is in the form of a wedge-shaped bladder 140 (FIGS. 11 and 11A) isinserted on one or both sides of the knee joint and expanded. Theretractor expands in a straight or curved shape depending on itsdimensions and easily separates the joint, creating a much enlargedworking space 142 (FIG. 11A), enabling the surgeon to operate via anyinstrument such as the scope illustrated schematically at 144. In asimilar manner, a surgeon can easily spread adjacent vertebrae in aspine to work on the spinal column, for example to remove a spinal discor any other tissue or bone. The bladder 140 may also be formed with acurved shape or otherwise custom-fit for the particular application.

The retractor 10 shown in FIGS. 12 and 12A operates similarly, with theexception that the bladder 146 is formed as a bellows-type device whichexpands in an accordion-like manner. The material of which thebellows-type bladder 146 is made does not necessarily stretch althoughit may somewhat, but rather the expansion comes primarily when thevarious surfaces are repositioned relative to each other. Theaccordion-like ridges 148 may be made of differing degrees of resistanceto straightening and flexing, in order to vary the rate and/or sequenceof inflation of various portions of the bladder 146. Alternatively, thematerial of which the bladder 146 is made has areas of rigidityinterleaved with areas of more elasticity, to provide the desiredexpansion effect. The ridges 140 may also be closure members that dividethe bladder 146 into a plurality of separate inflatable chambers withvalving therebetween, for sequential inflation. Such an accordion-likeor bellows construction can provide greater stability in intermediate(partially expanded) positions, and can have greater structuralintegrity.

FIG. 13 illustrates how a pair of retractors in accordance with thepresent invention can be used together to create a working space betweenthem. In the operation illustrated schematically in FIG. 13, the surgeondesires to retract a fat pocket or tissue 150 away from a knee 152 inorder to provide a working space 34 between them in which he canoperate. A cannula 154 is inserted through a small opening 156 in theskin 158 and through the fat pocket or tissue 150. An inner bladder 160is inflated inside the fat pocket or tissue 150, while an outer bladder164 is inflated on the outside of the skin 158. Drawing the two bladderstoward each other pulls the fat pocket or tissue 150 toward the skin andaway from the knee 152, thus creating the enlarged working space 34.This enables the surgeon to operate comfortably with a scope or otherinstrument 166, while still performing the entire operationpercutaneously as is, of course, desired, meanwhile stabilizing theinstrument.

In a somewhat similar manner, two separate retractors can be used tocreate a working space in between the two retractors. For example, FIG.14 illustrates the use of a pair of retractors to create and maintain anopen working space in a duodenum 170. A first retractor 172 is insertedthrough the stomach 174 on a scope or cannula 176 and is inflated at theupper end of the duodenum 170 to block it off from the stomach 174. Asecond retractor 178 is inserted through the stomach 174 on the scope orcannula 176 and is inflated lower on the duodenum 170 to block it offfrom the small intestine. An open working space 34 is thus createdbetween the retractors 172 and 178. The working space may be maintainedas long as both retractors 172 and 178 remain inflated. Such an openworking space is advantageous to enable a surgeon to better work on, forexample, a growth 180 in the duodenum 170. The retractor may also beused to block off an artery in a bleeding area of the bowel by directpressure.

Similarly, FIG. 15 illustrates the use of a pair of retractors inaccordance with the present invention to create a working space in ablood vessel. A first retractor 182 is inserted through a main bloodvessel 184 on a cannula 186 and is inflated to block the vessel 184 fromblood flow in one direction. A second retractor 108 is inserted throughthe vessel 184 on a separate shaft 190 through the cannula 186 and isinflated farther along the vessel 184 to block blood flow from a branchblood vessel 192. An open working space 34, free of blood, is thuscreated and is maintained as long as both retractors 182 and 188 remaininflated. Such an open working space can advantageously be used toenable a surgeon to better work, for example, with a scope 194 withinthe main vessel 184.

As noted above, an important advantage of the retractor of the presentinvention is that it can be used percutaneously to create a large actualspace within the body while making only a small opening in the skin.This allows for percutaneous or fiber optic surgery in locations whereheretofore only open surgery with its attendant disadvantages waspossible. This feature is illustrated in FIG. 16 which shows in solidlines a retractor 10 for insertion through a cannula 196 into an opening198 in skin 200. The retractor 10 is, at the time of insertion, nolarger in diameter than the opening 198. However, once inserted intolocation subcutaneously, the retractor 10 can be expanded to thecondition shown in broken lines to create a working space which asillustrated by the relative size of the arrow 202 is significantlylarger than the opening 198 in the skin 200.

The retractor illustrated in FIGS. 17-17C uses a bladder that is longerthan it is wide but which is hollow. To gain access to the surface 204of a bone 206, a small opening 208 is formed extending through the skin210 and the muscle 212. The opening 208 extends down to the surface 204of the bone 206. A retractor 214 (FIG. 17A) is then inserted, in anunexpanded condition, into the opening 208 and down into contact withthe surface of the bone. The retractor has an inner wall 215 and anouter wall 217 with a fluid space 219 between. The retractor 214 is theninflated, as seen in FIG. 17B, retracting the adjoining skin 210 andmuscle 212 radially outwardly. The retractor 214 has a hollowcylindrical shape with an opening 216 in the middle (see FIG. 17C). Theopening 216 is significantly larger than the opening 208. A surgical orother instrument can be inserted through the opening 216 from outsidethe body, into contact with the surface 204 of the bone 206, while theopening 216 is being maintained. Thus, a large opening can betemporarily created with only a small opening in the body tissue.

In a variation on the retractor shown in FIG. 17C, a retractor like theretractor 214 is shorter and has a ring shape when expanded. Theretractor is slid into the body tissue over a small pin such as a K-wirewhich has been used to pinpoint the desired area. The retractor is slidin while deflated, then expanded when at the desired location inside thebody. The inner diameter when expanded, though slightly less than theouter diameter, is still much larger than the size of the pin, forming alarge working and visualization space for the surgeon. The surface ofthe retractor may be roughened, ribbed, or serrated for better grippingpower to keep the retractor in place while expanded.

In another embodiment of the invention illustrated in FIGS. 18-18D, theone-piece bladder of the retractor 10 is replaced by a series of platesor filaments that are expanded radially or conically outwardly toretract the adjoining tissue. These plates or filaments may, asillustrated in FIGS. 18 and 18a, be rigid or semi-rigid elements 218which are expanded radially outwardly by a centrally located positioner220 which may be mechanical or which may be air-operated such as anexpandable bag. This is in the nature of a spring loaded umbrella with asleeve which slides over the ribs of the umbrella, which ribs open andexpand outwardly when the sleeve is pulled back. Alternatively, asillustrated in FIGS. 18B and 18C, the filaments 222 are hollowinflatable elements which themselves inflate upon application of fluidunder pressure to the retractor 10, straightening out as they fill withpressurized fluid. In either case, a sleeve 224 is preferably providedto protect and help locate or position the radially movable elements.The sleeve 224 slides axially. The plates or filaments are covered bysheath 224, which slides off them proximally axially to allow them to beexpanded radially outwardly to push tissue away from the scope toimprove visualization. After deflation, the sleeve 224 slides distallyalong the shaft over the filaments to cover them and allow the retractor10 to be moved through the body. A sleeve such as the sheath 224 canalso be employed in conjunction with a unitary bladder. In either event,the sleeve can be rigid or can be flexible.

Retractors in accordance with the present invention can also be used foropen surgery. FIGS. 19-19C are a series of schematic views illustratingthe use of a retractor of the present invention in open surgery. Theretractor is used to hold tissues laterally, pushing tissue edges apart.FIG. 19 shows the edges 226 and 228 on either side of an open surgicalincision or opening 230. As seen in FIG. 19A, an open surgery retractor232 has been inserted down into the incision 230. The retractor 232 isin the form of a hollow expandable tube that is bent into a V-shape or aU-shape for insertion into the incision 230. It may have a lip or ridgeon the surface engaging the tissue to better hold it in place. Thedeflated tube-like structure is first properly positioned within thewound 230. Upon inflation, the tube under fluid pressure attempts tostraighten itself out, and thus opens the wound 230 (FIG. 19B) foreasier access by the surgeon. As the retractor 232 presses on the edges226 and 228 of the wound, it also compresses the tissue edges, giving ahemostatic effect. The retractor may be a bladder that pushes two metalor plastic pieces out to the sides, rather than pushing directly on thetissue itself. If the retractor is put vertically into a wound (see FIG.19C) it expands the deep tissues. The depending legs 234 and 236 pushoutwardly as more fluid is admitted into the retractor, thus pushing thedeep tissues apart. This is accomplished without making acorrespondingly large opening in the skin.

As seen in FIG. 20A, a plurality of separately inflatable radiallyspaced bladders 246, 248, 250, 252, etc. can be located on one scope orcannula or rod 254. The bladders 246, 248, 250, 252 can be selectivelyinflated, possibly in a given sequence, to selectively retract tissue.

Alternatively, as seen in FIG. 20B a plurality of separately inflatableaxially spaced bladders 240, 242, etc. can be located on one scope orcannula or rod 244. The, bladders 240, 242 can be selectively inflatedto selectively retract tissue. One particular use for such a capabilityis to push a tube or other device down the stomach without it curlingback and up. FIG. 20C illustrates such a tube 260 having a plurality ofbladders 262A through 262F that are deflated. When it is desired toselectively rigidify a portion of the tube 260, the bladders 262Cthrough 262F are inflated (FIG. 20D), providing support for the tube attheir corresponding axial locations and rigidifying the correspondingportion of the tube 260 as desired.

When a plurality of separately inflatable bladders are located on thesame supporting device, suitable apparatus is provided for theirinflation. Such apparatus may be, when only a few bladders are present,a simple mechanical valving apparatus. When more bladders are present,or more sophisticated or complex control thereof is desired, amicroprocessor may be used to control the inflation. In such case, thecontrol signals may be multiplexed down the structure via optical fiberor wire, for example.

As further illustration of the variety of shapes of retractors which canbe used, FIGS. 21 and 21A illustrate the provision of pie-shapedretractors which create a working space between the edges of the pie.The supporting structure carries a pie-shaped retractor 272 which, wheninflated as shown, provides a space 274 for visualization and working.If two such retractors 272 are spaced axially as seen in FIG. 21A, anextended working and visualization area 272 is provided for the surgeon.

In the embodiment shown in FIG. 22, a bladder 280 is split at twolocations 282, 284 so that when inflated it provides working andvisualization areas between the lobes 286 and 288. Any number of suchlobes may be provided, as seen in FIG. 22A showing a bladder 290 havingfour such lobes.

A surface of the retractor may be reflective, to allow the surgeon tosee within the opening created by the retractor at different anglesrather than merely straight in. The retractor 292 (FIG. 23) has areflective surface or mirror 294 which enables visualization at an anglea which may be varied through inflation of the bladder 292 by variousamounts. This is an especially appropriate use for the bellows typeconstruction of the bladder as described above, wherein the surface ofthe bladder has a plurality of ridges 296. The retractor may thus beused to reflect light or a laser beam for visualization with a camera.Another suitable use for the retractors of the present invention is incarpal tunnel surgery that can be otherwise quite difficult. Theretractors are used to cup, move, and protect the nerves during theoperation. FIG. 24 illustrates schematically a sectional view through awrist 300 and showing the radius 302, ulna 304, median nerve 306, andtendons 308 and 310. A retractor 312 is inflatable radially outwardly inthe directions indicated by the arrows 314, to push the tendons 310 inthe direction indicated by the arrow 316 and away from the median nerve306. Thus, space is created adjacent the tendons and median nerve, at alocation axially from the retractor 312, for visualization and working.A second retractor 318 may be simultaneously used to create a longerworking and visualization space 320, as seen in FIG. 24A.

From the foregoing description of preferred embodiments of theinvention, those skilled in the art will perceive improvements, changesand modifications in the invention. Such improvements, changes andmodifications within the skill of the art are intended to be covered bythe appended claims.

What is claimed is:
 1. A method of providing a space between tissuelayers in the body for the performance of a surgical procedure, themethod comprising the steps of: making an incision in the body;introducing a surgical device through the incision, said surgical devicecomprising an insertion member and first and second inflatable bladders,said first inflatable bladder being spaced apart from said secondinflatable bladder; advancing the insertion member to position the firstinflatable bladder between the tissue layers at a location of a naturaltissue plane; inflating said first inflatable bladder to dissect a firstlayer of tissue from a second layer of tissue along the natural tissueplane; advancing the insertion member to position the second inflatablebladder between the tissue layers; and inflating said second inflatablebladder.
 2. The method of claim 1 wherein at least one of said first andsecond inflatable bladders is mounted on a tubular member.
 3. The methodof claim 1 wherein said first and second bladder positioning steps iscarried out at the same time.
 4. The method of claim 1 wherein saidfirst bladder remains inflated during the step of inflating said secondbladder.
 5. The method of claim 1 further comprising the steps of:deflating at least one of said first and second inflatable bladders; andperforming a surgical procedure in the space.
 6. The method of claim 5further comprising the step of removing at least one of said first andsecond inflatable bladders from the body prior to the step of performinga surgical procedure.
 7. The method of claim 1 wherein the space is aworking space, said working space being a volume not occupied by saidsurgical device or other device or by body tissue and sufficiently largeto perform a surgical procedure.
 8. The method of claim 1 wherein thespace is an anatomic space, said anatomic space being a volume notoccupied by body tissue.
 9. The method of claim 1 wherein the space isan open space, said open space being a volume not occupied by saidsurgical device or other device or by body tissue.
 10. The method ofclaim 1 wherein said first and second bladders are radially spaced aboutsaid insertion member.
 11. The method of claim 1 wherein said first andsecond bladders are axially spaced along said insertion member.
 12. Themethod of claim 1 wherein at least one of said first and second bladdersis mounted on said insertion member.